DE102011111786A1 - Method and apparatus for joining transfer or laminating film webs - Google Patents

Abstract

A method for connecting a first and a second film web (2, 2 ') of a transfer film or laminating film is described, wherein the film webs (2, 2') comprise a thermoplastic carrier film (21) and a decorative layer (23). Between the first and the second film web (2, 2 '), a common connecting portion (3) is formed, in which the first and the second film web (2, 2') are joined together by a welding process. Furthermore, an apparatus for carrying out the method will be described.

Description

The invention relates to a method and a device for connecting two transfer or laminating film webs, which comprise a thermoplastic carrier film and a decorative layer.

In the processing and application of transfer films and laminating film sections often need to be connected to each other in order to combine shorter film lengths or strips correspondingly longer "run lengths".

Certain run lengths result from both customer requirements, for example to increase productivity with high length cut rolls, and from the requirement to minimize rejects because set-up times or down times, especially for roll changing, are reduced.

In-house film production also requires the need to bond film webs together to increase productivity, minimize waste and reduce makeready times, downtime and start-up processes.

The most common method is the joining, also called "splicing", by means of, in particular, manually attached adhesive tapes. Here, the corresponding films are glued together with commercially available self-adhesive tapes. The bonding takes place in the case of laminating or transfer films (films coated on one side with a transfer layer) typically on the uncoated side of the film. The width of the adhesive tape is typically in the range of 2 to 5 cm. Typical thicknesses of adhesive tapes are in the range of about 30 to 130 microns.

Adhesive tape splicing has been proven in recent years and offers a number of advantages. The method is inexpensive, can be done with a relatively high registration accuracy of the films to each other and the splice, d. H. the joint or seam, has high strength, especially tensile strength in the direction of the films. In addition, colored adhesive tapes are often used to characterize certain types of splices and make them visually distinguishable.

However, splicing with adhesive tapes has a number of disadvantages.

When imprinting single images, these individual images or motifs, d. H. the benefits, arranged in a particular layout on the slide, especially in regular lines and tracks. As a rule, the benefits to be formed are so close together that the adhesive tape lies in the area of the embossing zone and in the area of the benefits to be embossed, so that these overlapped benefits are not noticeable and are lost. This can in particular lead to incorrect embossing and / or contamination of the embossing stamps by the adhesive tape or by the adhesive emerging from the edge of the adhesive tape. Therefore, the splice is detected and a sheet feeding is performed, whereby material loss occurs and productivity is lowered.

When imprinting single images on parallel tracks, there is an additional requirement that the splice points arrive at the embossing unit at the same time, since the embossing process must be interrupted on all tracks or all benefits must be skipped at the same time and all these benefits are lost. If the splices are in different places in the foils, the embossing process has to be interrupted for longer periods or has to be repeated several times.

When embossing single images by multiple application additional problems occur. Here, the repeat of the individual images, that is, the distance between the individual images to each other, must be very accurate. For this reason, only pieces of film with the same repeat can be spliced together.

Within spliced rollers, it may be due to the higher pressure - at the splice - to cold adhesive leakage at the edge of the splicing tape or "blocking" the Rolien, d. H. for gluing adjacent turns on the roll, come.

The use of adhesive tape splicing requires a higher control engineering effort.

The use of narrower adhesive tapes with a width of less than 1 cm is usually not possible because with narrow adhesive tapes the required strength, in particular tensile strengths during processing, can not be achieved with certainty and the splice also by tensile forces during winding or within the role can open.

The object of the present invention is to specify an improved method and an improved device which avoid the disadvantages mentioned.

According to the invention, this object is achieved by a method for joining a first and a second film web of a transfer film or laminating film, wherein the film webs comprise a thermoplastic carrier film and a decorative layer, and it is provided that a common connecting section is formed between the first and the second film web in which the first and the second film web are joined together by a welding process.

The object is achieved by a device for materially joining a first and a second film web of a transfer film or laminating film, wherein the film webs comprise a thermoplastic carrier film and a decorative layer, and wherein the decorative layer has motifs and / or registration marks, and it is provided that the device comprises receiving devices for the first and the second film web and at least one welding head, which is arranged above a connecting portion of the first and the second film web, and that at least one of the receiving devices is connected to an adjusting device in a manner of freezing motion.

Surprisingly, it has been found that a durable and strong welded joint occurs, although the film webs to be welded are formed as a multi-layer body, which in addition to the heat-sealable thermoplastic support film further layers that can reduce the strength of the weld or prevent it.

In addition, the films have a very good flatness after welding without disadvantageous thickening by an additional adhesive tape in the seam and show virtually no dimensional changes, especially one or two-dimensional distortions, which is for example for subsequent processes such as cutting and packaging processes of great importance ,

The transfer films are films whose decorative layer is transferred by means of an embossing tool by means of pressure and / or temperature to a substrate to be decorated. The base of the transfer film forms a carrier film of a thermoplastic material, on which a removable decorative layer is arranged.

The decorative layer can comprise, in addition to one or more decorative layers carrying the decor, further layers, for example an adhesive layer, an activation layer for the adhesive layer and a release layer to facilitate detachment of the decorative layer from a carrier film.

The one or more decorative layers may be formed, for example, in each case as an optionally colored, transparent, translucent or opaque lacquer layer, as a fluorescent or phosphorescent lacquer layer, as an optically variable layer and / or as a metallic or non-metallic reflection layer. Thus, a decorative layer may be formed as a pigmented lacquer layer, so that color effects can be formed and images and alphanumeric characters or symbols can be displayed. The decorative layer may be a functional layer, for example a magnetic layer, a photopolymer layer or a layer of conductive, semiconductive or non-conductive polymers. Films with such decorative layers can be used in the field of magnetic foils, for counterfeit protection of banknotes and documents, for outdoor applications, for example chrome foils for number plates or other decors, in the area of IMD or IML technology (IMD = In Mold Decoration; Labeling), for antenna applications as well as for labels of various applications. In addition, combinations of said decorative layers can be carried out, wherein in a decorative layer different layers are present directly or indirectly next to each other. The layer thickness of such a decorative layer is preferably between 1 .mu.m and 25 .mu.m, more preferably between 1 .mu.m and 5 .mu.m. An optically variable layer may be formed by a replicating lacquer layer having a molded, diffractive and / or refractive surface relief, a hologram layer, a volume hologram layer, a thin film layer system which generates color change effects by interference, a liquid crystal layer or a pigment containing layer, for example optically variable interference layer pigments or optically variable liquid crystal pigments or metal or metal oxide pigments. As a surface relief, for example, a refractive macrostructure, for example a lens structure, a diffractive diffraction grating or a hologram may be formed, which is preferably covered with a reflective layer. To assist the optical effects, metallic layers can be provided which reflect back incident light. The decorative layers may be formed differently in regions and combined with each other arbitrarily, so that, for example, OVD regions (optically variable device) and image regions are shown side by side or superimposed.

When laminating a separation of the decorative layer is not provided by the carrier film. An adhesive layer may therefore be provided between the decorative layer and the carrier film. The decorative layer may further include an adhesive layer in addition to one or more decorative layers. It may be a hot melt adhesive layer or a cold adhesive layer. The decorative layers may be formed like the decorative layers of the transfer film.

The individual layers of the film structure can be made of thermoplastic material, thermosetting material, for example, paints, which can be crosslinked by means of UV radiation, as well as of hybrid material (thermoplastic, ie thermal drying and crosslinkable at the same time with radiation) or combinations thereof.

The sequence of layers can also be multiple. It is also possible that a decorative layer of functional and / or decorative layers is present on both sides of the carrier film.

In particular, the release layers, which are preferably wax release layers, which soften upon hot activation heat softening and thereby perform their separation function, and of the metallization layers were expected to reduce the strength of the weld so much that a safe Connection of two film webs is not possible.

Surprisingly, with the method according to the invention and the device according to the invention, nevertheless, films can be spliced with high accuracy through a welded connection, whereby a connecting section is formed which leads to no production disturbance in the roll-to-roll process.

It can be provided that the common connecting portion is formed as a lap joint. The overlap impact can be formed with a particularly small width, so that films can also be spliced whose motif distance within the layout of the motifs is so small that, when using splicing tape, the motifs adjacent to the connection section would not be printable.

It can also be provided that the common connecting portion is formed as a butt joint which is covered by a splicing foil. However, the splicing film is not an adhesive tape, so that contamination by leakage of adhesive can not occur. The splicing film may also have a smaller thickness than an adhesive tape, in particular have a thickness of about 5 microns to 20 microns.

It may further be provided that the first and the second film web are joined together by means of ultrasonic welding.

In a further embodiment it can be provided that the first and the second film web are connected to one another by means of contact welding. In contact welding heated portions of the welding head are brought into thermal contact with the connecting portion, so that there is a local melting of the two film webs, which are thereby welded together.

It can be provided that a heated strip or a heated wire is used to form a weld.

It can further be provided that the first and the second film web are connected to one another by means of laser welding. It can be provided to move a laser along the weld and / or to optically deflect the laser light so that it forms a line.

It may be possible for an absorption layer for laser light to be arranged in the connecting section below the first and the second film web. The absorption layer converts the laser light into heat. This makes it possible in particular to use lower laser powers. Through the absorption layer, it is also possible to enter the energy acting on the weld also back of the weld, d. H. from the side facing away from the laser light. The absorption layer may be arranged as the uppermost layer or under another layer within a multilayer decorative layer. It is also possible to use a plurality of absorption layers, possibly at different positions within the decorative layer and possibly with different absorption characteristics for laser light.

In an advantageous embodiment, it may be provided that a splicing foil which absorbs the laser light is used as the absorption layer. However, the splicing film is not an adhesive tape, so that contamination by leakage of adhesive can not occur. Advantageously, it may be a colored film of the material of the carrier film.

The cut edges of the films may be rectilinear. It is also possible to use wavy-cut, perforated, serrated edges, etc.

It can be provided that a continuous weld is formed. In the simplest form, it may be a straight continuous single or multiple seam. The continuous weld can also be wave-shaped, serrated or meander-shaped. The welding head, for example the contact welding head, the laser beam or the sonotrode, can be moved over the film surface correspondingly to said seam contour or a correspondingly shaped welding wire can be provided.

It can also be provided that a discontinuous weld seam is formed. In particular, dashed or dotted weld seams can be formed by, for example, switching the laser beam on and off, the contact welding head or the sonotrode is switched on and off or lifted off the film surface and put back on.

It can further be provided that a weld seam is formed in an oscillating shape. In an oscillating weld, the position of the weld and / or the width of the weld may be varied. For example, the focus of the laser beam can be changed. It can further be provided to use contact welding heads or sonotrodes with an oblong cross section, for example a rectangular or elliptical cross section, and to turn or pivot them about their longitudinal axis. The width of the weld can be varied in this design by different effective widths of the welding head can be adjusted by the rotational position of the welding head. The effective width of the welding head thus varies between the dimension of the narrow side of the rectangle or the ellipse and the dimension of the broad side of the rectangle or the ellipse.

In a further advantageous embodiment it can be provided that the decorative layer is removed before the welding process in the region of the weld. The removal of the decorative layer can be done by bringing into contact with a self-adhesive tape with subsequent removal of the decorative layers or by prior transfer to a pad by means of, for example, a 3 mm wide heated embossing wheel.

Also possible is the previous modification, in particular ablation or thermal destruction, the decorative layer by means of laser action.

It can further be provided that the first and the second film web are aligned with one another in such a way that the motifs and / or registration marks arranged on the first film web are smaller than the motifs and / or registration marks arranged in the second film web in the connecting section in the register +/- 0.5 mm are aligned. If the subjects have clear contours, such as sharp edges and / or contours, registration marks can be dispensable.

Further claims are directed to the formation of the device.

It can be provided that the adjusting device is designed so that the arranged on the first film web motifs and / or registration marks to the arranged on the second film web motifs and / or registration marks in the connecting portion in the register with a position tolerance less than +/- 0 , 5 mm are alignable or vice versa. The adjusting device may comprise one or more measuring devices and one or more drive devices. The drive devices can be integrated, for example, in the receiving device. It may be linear motors, wherein the receiving device may comprise a cross table, which is movable in the x and y direction by the linear motors. The measuring device may comprise, for example, an electronic camera and a computer with image acquisition and processing software.

It can be provided that the at least one welding head is movable perpendicular to the surface of the film sections.

It can further be provided that the at least one welding head is rotatable about its longitudinal axis, as described above.

It can further be provided that the at least one welding head is movable transversely to the surface of the film sections in the x and / or y direction, in particular freely. This option may be preferred when splicing film webs whose width is greater than the working width of the welding head.

The welding head can be designed so that it can produce welds of any shape and pattern as well as single and multiple welds.

It can be provided that the at least one welding head is designed as a Ulltraschallschweißkopf. The welding head can have exchangeable sonotrodes, for example in order to be able to form different weld seam geometries.

It can further be provided that the at least one welding head is designed as a contact welding head. It may be provided a pulse operation in order to avoid a surface heating of the welding head.

In a further advantageous embodiment it can be provided that the at least one welding head is designed as a laser welding head. The welding device may have a specially configured, in particular low-adhesion pad (for example made of metal, silicone, Teflon, polyamide or the like). It is also possible, for example, in the form of a silicone support arranged between sonotrode and film surface pad. The welding device may further have means for cutting and / or fixing the films. Examples are suction devices, clamping and tensioning devices, pressure devices or combinations thereof.

The invention will now be explained in more detail with reference to exemplary embodiments. Show it

1a a first embodiment of an apparatus for connecting two transfer or laminating film webs in a schematic side view;

1b the device in 1a in a schematic plan view;

2a the interconnected film webs in 1a in a schematic perspective view;

2 B the interconnected film webs in 1a in a schematic sectional view;

3 a second embodiment of an apparatus for connecting two transfer or laminating film webs in a schematic perspective view;

4a a third embodiment of an apparatus for connecting two transfer or laminating film webs in a schematic sectional view;

4b the interconnected Folienabbahnen in 4a in a schematic sectional view;

5a a first preparation stage of the Folienendabschnitte for in

5c shown fourth embodiment of an apparatus for connecting two transfer or laminating film webs in a schematic sectional view;

5b a second preparation stage of the Folienendabschnitte in 5a ;

5c a fourth embodiment of an apparatus for connecting two transfer or laminating film webs in a schematic sectional view;

5d the interconnected film webs in 5c in a schematic sectional view;

6a a fifth embodiment of an apparatus for connecting two transfer or laminating film webs in a schematic sectional view;

6b the interconnected film webs in 6a in a schematic sectional view;

7a a sixth embodiment of an apparatus for connecting two transfer or laminating film webs in a schematic sectional view;

7b the interconnected film webs in 7a in a schematic sectional view;

8th the film-sealed Folienendabschnitte in the layer structure in a schematic sectional view;

9a a sectional view of a film welding connection in 10X magnification;

9b a sectional view of a foil welded connection in 20x magnification.

1a and 1b show a device 1 for connecting or splicing two transfer or laminating film webs 2 and 2 by ultrasonic welding in a schematic representation. In the in 1a and 1b In the embodiment shown, the foils are transfer foils designed as hot stamping foils.

The band-shaped foil webs 2 and 2 ' are on supply rolls 2v provided and recording devices 4 and 4 ' fed, which fix the end portions of the film webs. The film webs are present as a film roll, which in the device 1 be connected to larger film wraps. The films are multilayer bodies which comprise a thermoplastic carrier film and a decorative layer which can be pulled off from the carrier film and formed as a transfer layer. The films may have further layers, for example a separating layer arranged between the carrier film and the transfer layer, which facilitates the detachment of the transfer layer from the carrier film. Furthermore, reflection layers and protective layers can be provided, as described below 8th described.

The cradle 4 is with an adjustment device 4y motionless connected. By means of the adjusting device 4y is the cradle 4 adjustable in x- and y-direction, whereby the two film webs 2 and 2 ' are positionally adjustable with respect to each other. With the adjusting device 4y can the two film webs 2 and 2 ' be aligned with each other so that the on the first film web 2 arranged motifs and / or registration marks to those on the second film web 2 ' arranged motifs and / or registration marks are aligned in the register with a position tolerance less than +/- 0.5 mm and thereby a lap joint 3 form, in which they are arranged one above the other. The film webs 2 and 2 ' lie in overlap 3 on an anvil 5 on that under an ultrasonic welding head 6 is arranged. The ultrasonic welding head 6 includes an ultrasonic transducer 6w , an amplitude transformation piece 6a and a sonotrode 6s ,

To the ultrasonic transducer 6w a high-frequency alternating current is transmitted from which a mechanical ultrasonic vibration is generated by means of the piezoelectric or the magnetostrictive effect. The ultrasonic vibration is transmitted through the amplitude transformation piece 6a on the sonotrode 6s transfer. Due to the shape and mass of the amplitude transformation piece 6a the amplitude of the ultrasonic oscillation and the impedance matching are influenced. The sonotrode 6s can be made of steel, aluminum or titanium.

The sonotrode 6s points in the in 1a and 1b illustrated embodiment on two spaced-apart tips. The two tips of the sonotrode 6s come by lowering the ultrasonic welding head 6 with the overlap shock 3 on top of the film web 2 in abutment and transmit the ultrasonic vibrations to the film material. The anvil forms 5 an abutment for the sonotrode 6s , The ultrasonic vibrations are thus under pressure on the film webs to be joined 2 and 2 ' transferred in the overlap shock 3 on the anvil 5 are arranged one above the other. The with the sonotrode 6s in contact areas of the film webs 2 and 2 heat up because of the internal friction caused by the ultrasound and merge with each other.

The lowered ultrasonic welding head 6 is transverse to the longitudinal axis of the film webs 2 and 2 ' movable, so because of the two tips of the sonotrode 6s a double seam made of two parallel welds 3n can be produced (see 2a and 2 B ), covering the entire width of the film webs 2 and 2 ' are extended.

Surprisingly, it has been found that a permanent and strong welded joint occurs, although between the two carrier films in the lap joint 3 the said further layers are arranged so that the two carrier films are not in direct contact. It was to be expected that, in particular, wax also acts as a release agent during ultrasonic welding by melting due to the introduction of energy and prevents durable welding. Further down in 8th describes a possible mechanism of action leading to the load-bearing welded joint.

2a and 2 B show the interconnected film webs in 1 in a schematic perspective view or in a schematic sectional view. The film webs 2 and 2 ' are by a double seam, formed of two welds 3n , connected with each other.

As an alternative to the double seam of two rectilinear parallel individual seams, other double seams can also be carried out if the ultrasonic welding head 6 about its longitudinal axis (z-axis, according to the lowering direction) is rotatable. This also allows the two tips of the sonotrode 6s so during the rectilinear process of the ultrasonic welding head 6 transverse to the longitudinal axis or direction of the film webs 2 . 2 ' be twisted so that an oscillating double seam of two parallel, not straight individual seams. Depending on the size of the traversing and rotational speed, the resulting, in particular complex shape, in particular the density of the intersecting connecting seams, ie their respective distance from each other, can be controlled. The oscillating double seam can in particular be shaped similar to a guilloche. Such a close-fitting double seam can provide increased strength, in particular against tensile forces during processing and / or rolling up of the film webs 2 . 2 exhibit. It is also possible to equip the sonotrode with more than two tips, so that either straight parallel multiple seams arise or, as described above, correspondingly more complex, non-linear multiple seams. It is also possible to combine the multiple seams with the previously described width variations of the seam and / or seam breaks.

The 3 shows a second embodiment of the device 1 in which the sonotrode 6s as a roll sonotrode and the anvil 5 are designed as a roll anvil. The representation of the device in 3 Essentially, like the device in 1 is formed, is limited to simplify the presentation on the sonotrode and the anvil.

The 4a shows a schematic section of a third embodiment of the device 1 Essentially, like the device in 1 is trained. The two foil sections 2 and 2 ' butt together to form a butt joint and splice in the connecting portion 7 covered. The splice 7 Like the carrier film of the two film webs, it may consist of a thermoplastic plastic material. He knows the device 1 For example, be supplied as a tape which is cut to the width of the film webs after welding. As in 4b shown, a double seam can be provided, which consists of two welds 3n is formed. The advantage of this embodiment is that the two welds 3n directly between the thermoplastics which can be welded together Plastic materials are formed so that the welds are formed with optimum tensile strength.

The 5a to 5d show an embodiment in which the end portions of the film webs 2 and 2 ' each bent or folded by 90 ° and so a folding section 2f respectively. 2f ' form. This results in one of the welds 3n an increased strength, because by the folding in the folding section, the carrier films of the two film webs lie on each other and the carrier films against the direction of a subsequent tensile load interlock or interlock with each other.

The 6a and 6b show a further embodiment in which contact welding is provided as a connection method. Instead of the ultrasonic welding head in 1 is a contact welding head 8th provided, on its side facing the overlap shock underside two spaced wire or ribbon-shaped heating elements 8h which, when lowering the contact welding head 8th on the film webs to be joined 2 and 2 ' two welds 3n form by local thermal melting of the carrier films. Here too, mixed layers are formed in the welds, as described below 8th described.

The 7a and 7b show a further embodiment in which the film webs 2 and 2 ' be connected by laser welding. In the embodiment, two spaced laser welding heads 9 provided that a linear heating of the film webs to be joined 2 and 2 ' enable. These can be the laser welding heads 9 be designed to be displaceable along the seam axis, or it can not be slidable laser welding heads are provided with an optical beam deflection. The laser welding heads 9 facing top of the recording device is formed transparent to the laser radiation used. The two foil webs 2 and 2 ' form a butt joint under which an absorption layer formed as a black splice film 10 is arranged for the laser radiation. Under the splice foil is the anvil 5 arranged. The two foil webs 2 and 2 ' are advantageously aligned so that the carrier film rests on the splice film.

Is the contact welding head 8th with two or more heating elements 8h or the laser welding head 9 Equipped with two or more laser beams, so is it by twisting the contact welding head 8th around its longitudinal axis or in the case of the laser welding head 9 by rotation of the laser welding head 9 around its longitudinal axis or by appropriate adjustment of the optical beam deflection producing complex, in particular oscillating multiple seams with increased strength produced. It is also possible here to combine the multiple seams with the previously described width variations of the seam and / or seam breaks.

The 8th shows a schematic sectional view of the layer structure of two welded together film webs 2 and 2 ' as well as the formation of the welds 3n in detail.

The two foil webs 2 and 2 ' are designed as multi-layer body. On a carrier foil 21 , which may be formed of polyester, in particular PET (PET = polyethylene terephthalate), for example, is a waxy release layer 22 , a transfer situation 23 and a particular metallic reflection layer 24 arranged. The reflection layer can be made, for example, of metals such as aluminum, copper, chromium or HRI layers (HRI = high refractive index) such. As ZnS or TiO ₂ or from a multi-layer system over the entire surface or structured, z. B. be formed by partial metallization or demetalization. Combinations of these are also possible. As a further layer, for example, an adhesive layer may be provided.

As studies have shown, are in the welds 3n Mixed structures formed, wherein the carrier films 21 form a continuous connection layer in which clusters of the remaining layers are embedded. As the 9a and 9b show, a mixing of the layer package has occurred. Although the mixed layer is not as homogeneous as the carrier film, it still has sufficient tensile strength to allow the film to be imprinted or lamination, as described above.

As tests with different welding methods have shown, although the tensile strength of a conventional splice is not achieved, the minimum splice requirement for a splice greater than 13 N / cm is achieved. The tensile strength was determined in each case with a Zwick testing machine.

• – PET 19 μm: 21,5 N/cm
• – PET 50 μm: 47,0 N/cm

For ultrasonic welding bonds, the following tensile strengths resulted for films made of PET at a seam width of 0.8 mm, depending on the material thickness:

• PET 19 μm: 21.5 N / cm
• PET 50 μm: 47.0 N / cm

The starting material has a tensile strength of 40-45 N / cm at a thickness of 19 microns.

Conventional adhesive coated splice tape has a tensile strength of 30-40 N / cm. In a conventional splice and a PET film of 19 microns thickness, a tensile strength of 35-45 N / cm is achieved.

The inventively welded splice of o. G. PET material had a tensile strength of 15-25 N / cm, which is sufficient for further processing of the bonded film webs in a roll-to-roll process.

In a further experiment, film webs of a hot stamping film were bonded by ultrasonic welding with a seam width of 0.6-1.0 mm, the tensile strength per seam being 12-19 N / cm.

With a hot stamping foil with pigmented adhesive, only a tensile strength of 3.0 N / cm per seam was achieved with the same seam width of 0.6-1.0 mm.

• – Ultraschallschweißen (pro 0,5 mm Naht): 4,1 N/cm
• – Ultraschallschweißen (pro 1 mm Naht): 8,5 N/cm
• – Impulsschweißen bzw. Kontaktschweißen (pro 1,6 mm Naht): 12,8 N/cm

Further tests were carried out to determine the influence of the seam width and the welding process:

• - Ultrasonic welding (per 0.5 mm seam): 4.1 N / cm
• - Ultrasonic welding (per 1 mm seam): 8.5 N / cm
• - Impulse welding or contact welding (per 1.6 mm seam): 12.8 N / cm

Obviously, the width of the weld has a decisive influence on the tensile strength of the weld.

• – Herstellung einer Nahtstelle im Register mit +/–0,5 mm Toleranz;
• – Breite der Nahtstelle maximal 3 mm;
• – Auftragen der Nahtstelle, das heißt Dicke der Nahtstelle nicht größer als bei Ausbildung mit Spleißband;
• – Haftung so gut, dass die Folie die in einer typischen Applikationsmaschine auftretenden Zugkräfte übersteht;
• – Länge der Nahtstelle: im Bereich von 10 bis 650 mm,

The following requirements were imposed on the seam of the two film webs 2 and 2 ' posed:
As further shown, the following results could be achieved when joining foil webs of a hot stamping foil with a total thickness of about 19 μm:

• - Creation of a seam in the register with +/- 0.5 mm tolerance;
• - width of the seam maximum 3 mm;
• - Application of the interface, that is thickness of the interface not larger than when trained with splice tape;
• Adhesion so good that the film will withstand the tensile forces occurring in a typical application machine;
• - length of the interface: in the range of 10 to 650 mm,

LIST OF REFERENCE NUMBERS

1

Device for joining foil sections

2, 2 '

film section

2f, 2f '

folding section

2v

supply roll

3

lap joint

3n

Weld

4, 4 '

cradle

4y

adjusting

5

anvil

6

Ultrasonic welding head

6a

Amplitude transformation piece

6s

sonotrode

6w

ultrasound transducer

7

Spleißfolie

8th

Contact welding head

8h

heating element

9

Laser welding head

10

absorbing layer

21

support film

22

Interface

23

transfer layer

24

metallization

Claims (22)

Method for joining a first and a second film web ( 2 . 2 ' ) of a transfer film or laminating film, the film webs ( 2 . 2 ' ) a thermoplastic carrier film ( 21 ) and a decorative layer ( 23 ), characterized in that between the first and the second film web ( 2 . 2 ' ) a common connection section ( 3 ) is formed, in which the first and the second film web ( 2 . 2 ' ) are joined together by a welding process. A method according to claim 1, characterized in that the common connecting portion as a lap joint ( 3 ) is formed. A method according to claim 1, characterized in that the common connecting portion is formed as a butt joint which is covered by a splicing foil. Method according to one of the preceding claims, characterized in that the first and the second film web ( 2 . 2 ' ) are joined together by ultrasonic welding. Method according to one of claims 1 to 3, characterized in that the first and the second film web ( 2 . 2 ' ) are joined together by contact welding. A method according to claim 5, characterized in that for forming a weld an electric heating element ( 8h ) is used. Method according to one of claims 1 to 3, characterized in that the first and the second film web ( 2 . 2 ' ) are connected to each other by laser welding. A method according to claim 7, characterized in that in the connecting section below the first and the second film web ( 2 . 2 ' ) an absorption layer ( 10 ) is arranged for laser light. Method according to claim 8, characterized in that as absorption layer ( 10 ) a laser light absorbing splice foil is used. Method according to one of the preceding claims, characterized in that a continuous weld is formed. Method according to one of claims 1 to 9, characterized in that a discontinuous weld is formed. Method according to one of the preceding claims, characterized in that a weld seam is formed in an oscillating shape. Method according to one of the preceding claims, characterized in that the first and the second film web ( 2 . 2 ' ) are aligned with each other so that on the first film web ( 2 ) arranged motifs and / or registration marks to those on the second film web ( 2 ' ) arranged motifs and / or registration marks in the connecting portion ( 3 ) are aligned in the register with a position tolerance better than +/- 0.5 mm. Method according to one of the preceding claims, characterized in that prior to the formation of the weld in the region of the weld, the decorative layer ( 23 ) is removed locally. Contraption ( 1 ) for materially connecting a first and a second film web ( 2 . 2 ' ) of a transfer film or laminating film, the film webs ( 2 . 2 ' ) a thermoplastic carrier film ( 21 ) and a decorative layer ( 23 ), and wherein the decorative layer ( 23 ) Has motifs and / or registration marks, characterized in that the device ( 1 ) Recording devices ( 4 . 4 ' ) for the first and the second film web ( 2 . 2 ' ) and at least one welding head ( 6 . 8th . 9 ) which extends over a connecting section ( 3 ) of the first and the second film web ( 2 . 2 ' ), and that at least one of the receiving devices ( 4 . 4 ' ) with an adjusting device ( 4y ) is connected rigidly. Apparatus according to claim 15, characterized in that the adjusting device ( 4y ) is designed so that on the first film web ( 2 ) arranged motifs and / or registration marks to those on the second film web ( 2 ' ) arranged motifs and / or registration marks in the connecting portion ( 3 ) in the register with a positional tolerance better than +/- 0.5 mm can be aligned or vice versa. Apparatus according to claim 15 or 16, characterized in that the at least one welding head ( 2 . 8th . 9 ) perpendicular to the surface of the film sections ( 2 . 2 ' ) is movable. Device according to one of claims 15 to 17, characterized in that the at least one welding head ( 2 . 8th . 9 ) is rotatable about its longitudinal axis. Device according to one of claims 15 to 18, characterized in that the at least one welding head ( 2 . 8th . 9 ) transversely to the surface of the film sections ( 2 . 2 ' ) is movable in the x and / or y direction. Device according to one of claims 15 to 19, characterized in that the at least one welding head as an ultrasonic welding head ( 2 ) is trained. Device according to one of claims 15 to 19, characterized in that the at least one welding head as a contact welding head ( 8th ) is trained. Device according to one of claims 15 to 19, characterized in that the at least one welding head as a laser welding head ( 9 ) is trained.

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